They're the real deal, then. Sweet-Vapes only carries authentic coils. I'd double check the resistance and make sure they didn't send you the 1.2 ohm coils by mistake. 1.2 ohms is a gnat's hair away from the low resistance threshold... somewhere in the 1.2-1.4 ohm range. If they sent the wrong one, that's a good explanation as to why it'd fire briefly, then stop. The box should have a tickmark checked on it for resistance. The coils are all labeled, too. Also, the 1.5 ohm coils say 8-20 watts, the 1.2 ohm say 8-30 watts on the side.
If they did send you the correct 1.5 coils, your spinner might be on the way out.